Computer Science Lecture Notes

Introduction

• Live Stream: This lecture was live-streamed and will be uploaded later.
• Focus: Covering the entire syllabus of a computer science course, specifically the theory segment.
• Chapters: 8 chapters to be covered; official Cambridge IGCSE textbook used.
• Resources: Textbook and past paper questions for practice.

Chapters Overview

• Chapters Covered:
  • Chapter 1: Binary Systems and Hexadecimal Systems
  • Chapter 2: Communication and Internet Technologies
  • Chapter 3: Logic Gates and Circuits
  • Chapter 4: Operating Systems and Computer Architecture
  • Chapter 5: Input and Output Devices
  • Chapter 6: Memory and Data Storage
  • Chapter 7: High and Low-Level Languages
  • Chapter 8: Security, Ethics, and Data Integrity

Chapter 1: Binary Systems and Hexadecimal Systems

• Binary Systems:

  • Used in computers; languages understood by computers.
  • Binary numbers: 0 and 1 (base 2).
  • Conversion: Binary to Denary and vice versa explained.

• Hexadecimal Systems:

  • Easier alternative to binary for humans (base 16).
  • Conversion between binary, denary, and hexadecimal.
  • Uses: Memory dumps, HTML (colors), MAC addresses, web addresses, assembly and machine code.

Chapter 2: Communication and Internet Technologies

• Data Transmission:

  • Directions: Simplex (one-way), Half-Duplex (two-way, not simultaneous), Full-Duplex (two-way, simultaneous).
  • Methods: Serial (one bit at a time), Parallel (several bits simultaneously).
  • Synchronization: Asynchronous (agreed bit pattern with control bits), Synchronous (continuous stream with timing signals).

• Error Checking:

  • Methods include parity checking, automatic repeat requests, checksums, and echo checks.

• Internet Technologies:

  • ISPs, IP addresses, MAC addresses vs. IP addresses.
  • HTML and HTTP: Secure websites (HTTPS).
  • Web Browsers: Functions and features.

Chapter 3: Logic Gates and Circuits

• Logic Gates: NOT, AND, NAND, OR, NOR, XOR.
• Truth Tables and Logic Circuits: Constructing and understanding logic circuits using gates.

Chapter 4: Operating Systems and Computer Systems

• Operating Systems: Functions and uses.
• Interrupts and Buffers: Managing processes and temporary memory areas.
• Computer Architecture: Von Neumann architecture, buses (address, data, control).
• Fetch-Execute Cycle: Steps involved in processing instructions.

Chapter 5: Input and Output Devices

• Input Devices: Scanners, barcode readers, QR codes, digital cameras, keyboards, pointing devices, microphones, touch screens, sensors.
• Output Devices: Printers, 3D printers, cutters, actuators, speakers, monitors, projectors.
• Display Technologies: LCD, LED, OLED, projectors.

Chapter 6: Memory and Data Storage

• File Formats: MIDI, MP3, MP4, JPEG.
• File Compression: Lossy vs. Lossless compression.
• Storage Types:
  • Primary Storage: RAM (volatile) and ROM (non-volatile).
  • Secondary Storage: HDD (magnetic) vs. SSD (solid state).
  • Offline Storage: CDs, DVDs, Blu-rays, USB flash drives.

Chapter 7: High and Low-Level Languages

• High-Level Languages: Compilers, interpreters.
• Low-Level Languages: Assemblers.
• Translation Methods: How high-level and low-level languages are converted to machine code.

Chapter 8: Security, Ethics, and Data Integrity

• Security Threats: Hacking, viruses, phishing, pharming, spyware, cookies.
• Prevention Methods: Firewalls, strong passwords, anti-virus software, ISP filters.
• Ethical Considerations: Data protection laws, ethical use of computers.

Conclusion

• Revision and Practice: Encouraged to use textbook notes and past paper questions.
• Live Stream Success: Comprehensive coverage of theory syllabus.